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Experimental Methods to Study Human Postural Control
Published on: September 11, 2019
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Unintentional movements induced by sequential transient perturbations in a multi-joint positional task
Tao Zhou1, Ali Falaki1, Mark L Latash2
1Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA.
Human Movement Science
|December 26, 2015
Summary
Repeated robotic forces cause accumulating unintentional arm movements due to a referent coordinate (RC) drift. This drift also alters limb stiffness, indicating a slow resetting process in motor control.
Area of Science:
- Motor control
- Biomechanics
- Robotics
Background:
- Unintentional movements can arise from external forces.
- Understanding motor adaptation to perturbations is crucial for rehabilitation and human-robot interaction.
Purpose of the Study:
- To investigate unintentional limb movements caused by repeated transient external forces.
- To examine the effects on limb apparent stiffness and referent coordinate (RC) drift.
Main Methods:
- Subjects performed a position-holding task against robotic bias forces.
- Repeated force perturbations were applied, inducing unintentional arm movements.
- Limb apparent stiffness and movement distances were analyzed across perturbations.
Main Results:
- Accumulated movement and undershoot distances increased with sequential perturbations.
- Limb apparent stiffness increased before dwell time and decreased after dwell time.
- Results suggest a referent coordinate (RC) drift and coupled stiffness changes.
Conclusions:
- Repeated perturbations lead to accumulating unintentional movements via RC back-coupling.
- A slow resetting process accompanies the drift of the referent coordinate and apparent stiffness.
Keywords:
Apparent stiffnessBack-couplingEquifinalityReferent configuration hypothesisUnintentional movement
